In Kandahar, Afghanistan, the U.S. troop buildup has led to a drop in Taliban attacks, but residents say militants are hiding in plain sight.

Reporting from Kandahar, Afghanistan — The former Taliban commander was furious, chain-smoking, scowling and scattering ashes on a plastic mat spread on the dusty ground.

He deeply regretted, he said, that he had defected to the Afghan government side this year with nearly two dozen of his men, one of whom has already been hunted down and killed in revenge. And he did not believe that his former comrades in arms in the insurgency were ready to give up the fight for their traditional heartland.

With this year's fighting season drawing to a close as the harsh Afghan winter sets in, U.S. commanders have declared that the "surge" ordered by President Obama two years ago achieved its aims.

"Militarily, the surge worked," Gen. Martin E. Dempsey, chairman of the Joint Chiefs of Staff, told journalists in London last week.

A crucial goal of the troop buildup was breaking the insurgency's hold on Kandahar, the Taliban's birthplace and a center of gravity for all of southern Afghanistan. But even as the NATO force reports an overall drop in insurgent attacks against Western troops during the fighting season, many here question the durability of gains against the Taliban, whose roots in this city run too deep to be readily eradicated.

Longtime residents murmur uneasily that the insurgents, many of them drawn from Kandahar and its surrounding farm districts, are simply lying low, sometimes in plain sight.

"They are never really gone," said Umar Sediq, a Kandahar merchant. "You walk down the street and say: 'Oh, yes, there is that one, and that one. And that one."

In a key sign of recalcitrance on the part of Taliban fighters, few of those from Kandahar have joined an ambitious government reintegration program, meant to lure fighters from the battlefield. Only 83 insurgents have switched sides in Kandahar province, less than one-twentieth of the total across the country, despite the area's importance as a center of the insurgency.

One defector was Mullah Tor Jan, a disgruntled veteran field commander who spent the better part of a decade battling Western troops in Kandahar and neighboring provinces. Tiring of the fight, he turned himself in this year, hoping for a government job.

Now, he describes himself as a virtual prisoner in a garrison district of Kandahar where Afghan military families are housed. He has no work; his large family lives in a squalid two-room structure. The Taliban killed one of the 23 men who joined the reintegration program along with him.

"They send me messages," he said of his former fellow fighters. "Sometimes they threaten me, but they also taunt me for being tricked. They know the government didn't keep its promises to me and the others."

Tor Jan's relations are also rocky with the Afghan security forces, which he had once hoped to join, preferably in a position carrying something of the authority and prestige he had in the Taliban movement. Recently, two of his relatives in nearby Arghandab district were arrested on suspicion of having links to the insurgency, a development he took as a grave personal affront.

In Kandahar, switching sides is an extremely dangerous proposition. The Taliban may have trouble mounting organized attacks against Western troops, but the fighters have shown extraordinary determination to exact vengeance against those who leave the ranks.

Another Taliban commander who came in from the cold was Noorul Aziz, who was seriously wounded in October when assailants tossed a grenade into his vehicle, the latest of several attempts by insurgents to assassinate him. He remains active in the reintegration effort, but said the authorities had endangered fighters who wanted to turn themselves in by parading them before TV cameras.

"That's a mistake, showing their faces," said Aziz, who was given the post of provincial director for the hajj, the pilgrimage to Mecca, after turning himself in this year.

Efforts to bring the Taliban leadership to the bargaining table, a process that Western officials had hoped would coincide with the troop buildup, have faltered in recent months. Officials had hoped that Pakistan, a key intermediary with the insurgents, would take part in an international conference in Bonn, Germany, this week, but the Islamabad government is boycotting the gathering to protest the deaths of 24 of its soldiers in an apparently mistaken NATO airstrike.

Without political progress toward a settlement, military gains can be difficult to cement. After last year's fighting season, the North Atlantic Treaty Organization force declared that it had dislodged the Taliban from three key districts surrounding Kandahar: Arghandab, Panjwayi and Zhari. Arghandab has remained relatively peaceful, but Zhari and Panjwayi are considered "contested," said German Brig. Gen. Carsten Jacobson, a spokesman for NATO's International Security Assistance Force.